package com.hmdp.utils;

import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Slf4j
@Component
public class RedisIdWorker {

    // 2024年 开始时间戳
    private static final long BEGIN_TIMESTAMP = 1704038400L;
    private static final long COUNT_BITS = 32;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    public long nextId(String keyPrefix) {
        // 1.生成时间戳
        LocalDateTime dateTime = LocalDateTime.now();
        // 获取当前时间戳
        long nowSecond = dateTime.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;
        // 2.生成序列号
        String date = dateTime.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        // 获取当前日期 Redis的increment方法确保在分布式环境下的序列号唯一性和递增性
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);

        // 3.拼接并返回
        return timestamp << COUNT_BITS | count;
    }
}
